| Sulige gasfield is the largest natural gasfield in china now which is discovered and developed,is a typical lens multi-layered stacked tight sandstone gas reservoirs,the reservoir is low porosity,low permeability,low abundance and strong heterogeneity.Single well production and controlled reserves are low,difficult to achieve the scale of the tight sandstone gas reserves effectively utilized as long plagued Sulige gasfield scale development of the core issue.In-depth analysis of the Sulige gasfield geology,reservoir,drilling and completion engineering information to identify the main technical bottlenecks which restrict the productivity of single well in Sulige gasfield:①Main sand body drill in low rate,low single well control reserves;②the reservoir protective effect is not ideal,it is difficult to reveal the original production capacity of gas wells;③there is no natural capacity in non-rich region,yield unsatisfactory.For rich region,branch horizontal well with good reservoir protection technology,can effectively reveal the original capacity;for non-enrichment block,cooperate level period of open hole fracturing reconstruction of branch horizontal well drilling and well completion technology is its economic capacity of the most promising technology system,so it is necessary to carry out the applicable to gas branch horizontal well integrated technology research in Sulige gasfield.(1)Preferably select the suitable for Sulige gasfield the special drilling and completion engineering geological environment of well construction and borehole profiles through comparative study and system analysis,as well as the branch well sidetrack and reentrant technology,and developed a controllable centralizer and retrievable whipstock and other supporting tools.(2)For Sulige gasfield wellbore stability problems,respectively studied "double stone layer" and the wellbore instability mechanism of the coal seam section and branch joint,and the related theoretical model is established in this paper.For "double stone layer" and seam segment,developed a strong inhibition of potash anti-collapse polymer drilling fluid system;for branch junction,developed a window sealing liquid system which can improve branch junction formation pressure capacity.(3)We established branch horizontal wellbore coupling seepage flow model which considering variable mass flow and wellbore near wellbore formation,as well as the tripping wellbore pressure transient wave mathematical model.(4)For low permeability of tight sandstone reservoir protection issues,through the system indoor experimental and theoretical studies,found out the main factors of reservoir damage caused by,thus developed can effectively protect the oil reservoir of aqueous soft temporary plugging drilling and completion fluid system.(5)The Sulige branch horizontal well with two open well structure,request return to cementing long open hole section at a time,take into account the friction problem of casing and anti-gas channeling characteristics,anti-gas channeling GSJ cement slurry is developed for this system and developed a rigid spiral roller centralizer and other supporting cementing tools.(6)Preferred experimental branch horizontal well completion system suitable for Sulige gasfield;optimized fracturing parameters for reservoir reconstruction,developed a full range of the open hole staged fracturing transformation tools,and the development of low damage low friction resistance fracturing fluid system.(7)In Sulige gasfield peach 7 blocks to carry out the two wells of branch horizontal well in integrated technology field application test,the results show that the core technology of the current set of technical system effectively and reliably at present,compared with conventional drilling reflects the outstanding technical and economic advantages,preliminary meet the requirements of Sulige tight sandstone gas reservoir to improve the single well production and controlled reserves. |
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